1. Field of the Invention
Example embodiments of the present invention relate to a siloxane polymer composition, to a method of forming a pattern, and to a method of manufacturing a semiconductor device. More particularly, example embodiments of the present invention relate to a siloxane polymer composition for forming a siloxane layer capable of effectively filling an opening, to a method of forming a pattern using the siloxane polymer composition, and to a method of manufacturing a semiconductor device using the siloxane polymer composition.
2. Description of the Related Art
In general, a capacitor in a semiconductor memory device, e.g., in a dynamic random access memory (DRAM) device, may include a bottom electrode, a dielectric layer, and an upper electrode. To improve storage capacity of the semiconductor memory device, the capacitor may have a large capacitance despite its reduced size. For example, in a DRAM device having a large storage capacity, e.g., above one Giga bites, the capacitor may have a volumetric structure, e.g., a box structure or a cylindrical structure, with a high aspect ratio.
A conventional volumetric capacitor, e.g., a cylindrical capacitor, may have, e.g., a cylindrically shaped lower electrode, a dielectric layer, and an upper electrode. The conventional cylindrically shaped lower electrode may be formed using a photoresist buffer layer or an oxide buffer layer, e.g., during a process for separating or patterning adjacent lower electrodes.
For example, a conventional photoresist buffer layer may be formed by depositing a photoresist film on the lower electrode, followed by performing an exposure process, a developing process, a cleaning process, and a baking process on the photoresist film. Next, the photoresist film may be dried, e.g., using an isopropyl alcohol (IPA) solution, and removed, e.g., once adjacent lower electrodes are separated, via a plasma ashing process.
The processes in the conventional formation of the photoresist buffer film, however, may require an expensive exposure apparatus. Further, the conventional baking process may require baking the photoresist film at a relatively high temperature of about 270° C. or higher to prevent contamination of the drying apparatus, thereby making the subsequent removal of the buffer layer from the lower electrodes via the plasma ashing process difficult. As a result, since some portions of the conventional photoresist buffer layer may not be easily removed from the lower electrode by the plasma ashing process, remaining portions of the photoresist buffer layer on the lower electrode may cause an electrical failure of the capacitor. In addition, the plasma ashing process and a subsequent cleaning process for removing the conventional photoresist buffer layer from the lower electrode may deteriorate and/or oxidize the lower electrodes, e.g., when the plasma ashing process is performed at a relatively high temperature of about 150° C. to about 250° C. to improve removal of the conventional photoresist buffer layer. As a result, a volumetric capacitor having a conventional, e.g., cylindrically shaped, lower electrode may have low capacitance and poor electrical characteristics.
In another example, a conventional oxide buffer layer may be formed, e.g., by performing a spin coating process, a baking process, and an etch-back process. The conventional oxide buffer layer, however, may have poor flatness, i.e., may have non-uniform thickness, when formed in an opening having a relatively high aspect ratio by the spin coating process. When a cylindrical lower electrode is formed using a buffer layer having non-uniform thickness, lower electrodes of capacitors in a unit cell of a semiconductor memory device may have different heights, thereby having different capacitances. As a result, the semiconductor memory device may have poor electrical characteristics due to the non-uniform capacitance.